Method and apparatus for forming outside curls



July 17, 1934. MUNGEN 1,967,192

METHOD AND APPARATUS FOR FORMING OUTSIDE CURLS Filed June 30, 1950 Sheets-Sheet l INVENTOR.

THEODORE MUNGEN ATTORNEY.

July 17, 1934. T. MUNGEN METHOD AND APPARATUS FOR FORMING OUTSIDE CURLS Filed June 30, 1930 3 Sheets-Sheet 2 INVENTOR. THEODORE MUNGEN BY /T ATTORNEY.

July 17, 1934. T. MUNGEN METHOD AND APPARATUS FOR FORMING OUTSIDE CURLS Filed June 30, 1930 3 Sheets-Sheet 3 FICLB ATTORNEY;

Patented July 17, 1934 AND APPARATUS FORMING DUTSIDECURL'S Theodore Mungen, Philadelphia, Pa., assignor .to Edward G. Budd Manufacturing Company, Philadelphia, -Pa., a corporation of Pennsylvania Application June so, 1930, Serial No. 464,786

14 Claims. (o 153-48) This'invention relates to a method and an apparatus for forming partial or-compiete outside curls in sheet metal strips. The invention particularly relates to the formation of outside curls in circular sheet metal bands to form a circular and substantiaily tubular ring-like construction for use in a great variety of sheet metal constructions. Among the uses that have been found for such circular constructions are the formation of cores for reinforcing vulcanized steering wheels; the formation of chime seams for barrels, circular containers, circular seat bottoms, circular tubing such as smoke stacks and the like, and in fact for the formation of all manner of curvilinear struts, ribs or hoops whether large or small.

Heretofore the general methodof forming curls in sheet metal strips has been to wind such strips around a mandrel, with or without the applica tion of heat. Such a method possesses the disadvantage that the curl so formed is not compact and consequently cannot advantageously be used as a strengthening member in certain constructions. Furthermore such a method of forming outside curls is not applicable to curvilinear constructions.

A second method of forming curls in sheet metal constructions, wherein the use ofcircular dies is involved, is disclosed in the patent to Draper 1,466,643, August 23, 1923; This method is known as the outside curling process and involves a great number of detailed steps including the formation of a circular band bybutt welding adjacent edges of a sheet together andthe formation of a preliminary initial 'flared'edge'before the curling operation takes place. The present inventionis designed as an improvement over such a method as is disclosed in the above men-' tioned patent, and as animprovement in the ap paratus employed in forming outside curls in sheet metal constructions.

Accordingly it is an object ofthepresent lnvention to provide a method and an apparatus for performing the outside curling operation on a sheet of material which will effectively form a closed circular curled'member from a strip of sheetmaterial' without the necessity of relying on a welding operation for maintaining the fine ished article closed. It is also an object of the $0 present invent-ion to provide a methcd'and an apparatus for forming such articles which will also elim-inatc the necessity of mill rolling or otherwise forming an initial bend inthe material to insure proper formation' oii the subsequent die curling operation.

A still further object or the invention is to provide a machine for forming outside curls upon sheet metal in which the curling operation is positive in its action on the sheet of material being formed, means being provided for expand ing the material into the form of a. true ciiicle prior to its introduction into the die.

Yetanother object of thepresent invention is to provide an apparatus which may successively operate upon diife'r-ent sheets of material to form an outside curl, means being provided whereby each preceding article may easily, with a mini-- mum amount of time involved, be removed from the machine to make room for the succeeding blank to be introduced into the apparatus.

Still another object of the invention is to provide an apparatus which operates upon circular bands of sheet materialize form an outside curl and which may, by proper forming of the die, shape the finished article into any desired closed form, and to any desired cross sectional area or which may form the article so as to have a nonuniform cr'oss sectional area.

Another and important object of the invention is to provide an apparatus which may operate not only upon bands that have been pro-formed into circular shape, but which may operate upon band's thctendency of which is to assume a position in a plane, means being provided whereby the inherent characteristic of the apparatus itself will permit the insertion oi. fiat strips of material into the same by coiling them in th'e'machine runway in circular form. V This latter feature eliminates the necessity of special apparatus for forming the fiat material into ring-shaped form prior to its introduction into the machine.

An additional object or the invention is to provide ran-apparatus which will form a smooth ring-shaped article if desired and which may also form an article having peripheral striations and a general rough appearance to prevent drifting of the rubber body material and insure close adherence of the same when" the article is to be used as a steel core for steering wheels or the like.

Still another object of the invention is to provide an apparatus for forming outside hollow curls from sheet metal whichcurls are practically fluid tight so that when the article is used as a. core in a plastic composition, there will be no seepage of the composition under pressure in the vulcanizing molds into the interior of the write deprive an outside region of the article iromsuflicient material to do justic'eto proper iormation or the: article;

Another object of the invention is to provide an apparatus which apart from the introduction into, and the removal from, the machine, of the material to be treated and the finished article respectively, is entirely automatic in its operation and involves a minimum amount of work to be performed by the operator.

Another object of the invention is to provide a machine which is extremely simple in its construction and which employs a minimum number of moving parts. Convenience of arrangement of parts, durability and comparative inexpense of maintenance are further desiderata that have been borne in mind in the production and development of the invention. v

A number of exacting tests of cores for steering wheels employing the present improvements have demonstrated that the type of reinforcing ring formed by the present apparatus maintains the inner and outer curl seam effectively intact under conditions that will produce damage and leakage in similar reinforcing rings or ribs manufactured by other well known processes. The material in this method becomes deformed and bends together as a unit instead of separating under great stress as usually occurs with older methods of manufacture. This latter feature arises from the fact that the laps of the curl are, by the outside method of curling, caused to bear against eachother with great force so that any subsequent deformation of the ring will not separate or buckle the layers.

' Other objects and advantages ofv the invention, not at this time more particularly enumerated will become more readily apparent as the nature of the invention is better understood, and the same consists in the novel construction, combination and arrangement of parts shown in the accompanying three sheets of drawings in which:

Fig. 1 is a top plan view of the machine assembly with the upper die removed for the purpose of illustrating the invention. Fig. 2 is a sectional view taken through the machine assembly showing the parts in closed position.

Fig. 3 is a sectional view showing theassembled machine the parts being in open position.

Fig. 4 is a plan view of one of the articles formed by the improved die shaping machine.

Fig. 5 is a fragmentary perspective view show ing one of the articles formed from a single sheet of material.

Fig. 6 is a view similar to Figure 5 showing the article formed of a double thicknessv of sheet material.

Fig. 7 is a fragmentary perspective view show-. ing a different form of article capable of being manufactured by'the improvedapparatus, and

FigJSis a detailed fragmentary-sectional view of the closed assembly. r I In all of the above described views, like characters of reference are, employed to designate like parts throughout. V

The device involves in its general organization a pair of standards, 10 and 11, mounted on a foundation, 12. The standards,'10 and 11, carry therebetween a bed, 13, on which there is mount ed a bolster, 14, which is removably secured thereto. Mounted" on the bolster, 14, is a lower die base plate, 15. 'This lower die base plate, 15, carries a lower. die holder, 16, which is removably secured thereto by means of 'bolts,-'17,"which ex-' tend through'the lower die base plate. The lower die holder is annular in form and is provided with an internal annularsshoulder, 18, oniwhich is mounted the lower die, 19. This lower die is removably secured to the holder, 16, by means of through bolts, 20, extending into the die.

The lower die base plate, 15, and the bolster, 14, are provided with bores, 21, extending .therethrough in alignment and through which bores extend a pair of thrust rods, 22, carried on a floater, 23, slidably mounted for vertical movement within the lower die assembly. The thrust rods, 22, have their lower ends connected to a head, 24, -carrying"a' piston, 25, working in a cylinder, 26, suspended by a tie rod assembly, 27, from the bed, 13.

The upper die assembly is slidably carried between the gibs; 10' and 11, and comprises the blank holder of the press, 28, having an annular blank holder plate, 29, to which is secured a spacing member, 30, carrying the upper die blank holder, 31. The upper die, 32, is removably secured in a cut-away portion, 33, in the blank holder, 31,- by means of through bolts, 34, extending through the blank holder.

The upper die, 32, and the-lower die blank, 19, are adapted to be closed upon each other to cooperate in the machine to perform an outside curling operation upon a narrow ring-shaped band when this sheet is introduced forcibly be tween the dies. To this end the lower die is in the form of a ring having an annular recess, 35, extending adjacent its inner upper edge around the same. The upper die similar in shape and is provided with a similar recess, 36, extending around its lower surface adjacent the inner edge thereof. The two dies are positioned in the machine in superimposed relation with the upper die spaced from the lower die to permit insertion of a blank, 37, into the machine.

The upper die, 32,is adapted to be closed upon the lower die, 19, to form an annular pocket, substantially circular in cross section, in which pocket the blank is adapted to be forced to perform the outside curling operation upon the die. The inner wall, 38, of the lower die, 19, presents a cylindrical surface which is slightly smaller in diameter than the diameter of the cylindrical surface presented by the inner wall of the upper die, 32. Thus, when the dies are in closed position, anarrow slot, 38' (Fig. 8) leading into the interior of the pocket formed between the two dies, 19 and 32, is formed to permit tangential entryof the blank-edgeways.

In order to properly position and hold the blank in the machine preparatory to the performing of the outside curlingoperation, a floater, 23, is provided within the lower die assembly and is secured to the thrust rods, 22. The floater, 23, is provided with a plurality of radial bores, therein, designated at=39, terminating in slots, 39, and having guide pins, 40, around which are disposed coil springs, 41, the ends of whichbear against pins, 42, receivable in holding blocks, 43, radiallyslidable. upon the floater, 23. These blocks are in theform of segments and are preferably four innumber, although a greater or lessernumber of these blocks may be employed if desired. Each block is provided with a plurality of elongated slots, 44, therein, in which slots there extends a number of fixed pins, 45. The slots, 44, extend radially of the machine and consequently each of the blocks is slidable to contract or expand in unison. The outer sides of the blocks, 43, are accurate in shape, and are of a curvature corresponding to the curvature of the sheet metalblanks.

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hret htt 2 b t The upper die assembly has be gl qvided in the la e-t nt nst nc t n A th h ttm g zgrlth t will be entirely filiigl ti ht when termed t 'a b em q e QOIQTOIIT mterie l, ti; th i th ev th is mpl d o fqr tl 16.1 59? h 1? th tohh t h a sir heme in tt ih m t imes to); tqhttihere the iiifiper die assembly may entirely be. gi sp gnggg q wi h and me Qt si @911 m e harmed, d r t th iq the FUQiQ- t g new 9 Eig urt 8, the low r die htiihs h v ded. W1 h extthd 35, in the same. Mounted within this bore is a who plug, 86, serving to support a'steel ball, 87, a portion of which extends upwardly within the recess. A number of these steel balls may be so positioned around the recess as to cause a number of circular corrugations, 88, to be formed around the finished ring which corrugations serve, when the ring is to be employed as a steel core for vulcanized rings, to prevent spreading of the rubber in the moulds.

It is obvious that other projections may be positioned or formed in the mould to cause any desired irregular cross-sectional deformations of the finished article. Furthermore, the entire inner surface of the mould may purposely be roughened to leave a number of minute striations on the interior surface of the finished article to further prevent migration of the rubber on the same when in the mould.

In Figure 7, the article is shown as being formed with flange, 89, left thereon. Such a flange may be formed on the article by limiting the stroke of the punch, 48. The stroke of the punch may be lengthened or shortened at will to decrease or increase respectively the length of this flange. This flange is admirably adapted for attachment by riveting, welding or the like to the article to which the device is to be applied.

In the accompanying drawings, an apparatus has been disclosed for performing outside curls upon sheet metal construction, yet it is contemplated by the reversal of certain of the parts, especially the dies in this device, to form inside curls of sheet metal bands. With the internal curling, the circumferential stresses inv the edge of the metal as it travels inwardly, are tensile instead of compressive, and where very light sheet metal is employed this latter method of curling is contemplated in accordance with the principles of the present invention.

The invention is not to be limited to the exact arrangement of the parts shown in the accompanying. three sheets of drawings, or described in the present specification, as many changes in the construction of the various parts (as for example the use of inside instead of outside curling dies) is contemplated. Only in so far as the invention is particularly pointed out in the accompanying claims is the same to be limited.

What I claim is:

1. The method forming a closed ring-shaped curl which comprises providing a retaining means for holding a flat strip of sheet material in the form of a cylinder, placing a sheet of material in said retaining means, placing a second sheet of material in said retaining means with the edges of one sheet of material coming into proximity with each other at a point remote from the point where the edges of the other sheet of material come into proximity, and rolling the edges of said sheets simultaneously to form a single curl of double thickness.

2. The method of forming a ring-shaped cu which comprises bending a plurality of sheets of material into the form of bands, placing said bands within each other with adjacent longitudinal edges of each band remote from the'adjacent edges of each other band, and rolling the cylindrical edge of said bands simultaneously into a curl.

3. The method of forming a closed ring-like structure which comprises forminga pair of strips of sheet material into the form of bands, placing one band Within the other with adjacent longitudinal edges of each band at points remote from each other, and rolling adjacent cylindrical edges of the bands simultaneously.

' 4. A machine for forming curls in sheet material comprising a lower die having an arcuate recess formed therein, an upper die having an arcuate recess therein, means for bringing said dies into position adjacent each other with the recesses opposing each other to form a recess of circular cross section, having a peripheral opening therein, and means for forcing a sheet of material intothe peripheral opening thus formed between the dies to cause the same to follow the inside curvature of the recess and form a curl.

5. An apparatus for forming curls in sheet material which'comprises a bed having a lower die mounted thereon, an upper die holder movable with respect to said bed, a die mounted on said die holder for movement therewith, said dies having opening recesses therein, and a floater slidably mounted within said lower die and adapted to receive a sheet of material therearound, said floater member forming with an edge of said upper dies a guide for a band of sheet material, means for closing said upper die and said lower die, and a punch for engaging the upper edge of said sheet material, andforcing the same endwise into the recesses between said dies.

6. An apparatus for forming curls in sheet material which comprises a lower die assembly and an upper die assembly, including upper and lower dies respectively, means for moving one of said dies into close proximity with the other of said dies, said 'dies each having a recess therein adapted when said dies are in close proximity to form a tubular restriction, a floater member forming with an edge of one of said dies a guide for a strip of sheet material, means upon said floater member for forcing a strip of said material inserted within the guide firmly against one of the dies to position the same for curling, and means for sliding the sheet of material into the recesses in said dies to form a curl.

'7. An apparatus for forming outside curls in sheet material which comprises a lower die assembly and an upper die assembly including upper and lower dies respectively, means for causing said upper die assembly to move with respect to said lower-die assembly to bring said dies in close proximity, said dies being ring-shaped in form, and having recesses therebetween when closed upon each other, a floater mounted within said dies and adapted to form with said upper die a guide therebetween for a band of sheet material, and means for engaging the upper edge of a band of sheet material within said guide for forcing said sheet material endwise into the recess between said dies.

8. An apparatus for forming outside curls in sheet material which comprises a lower die assembly and an upper die assembly including upper and lower dies respectively, means for causing said upper die assembly to move with respect to said lower die assembly to bring said dies in close proximity, said dies being ring-shaped in form, and having recesses therebetween when closed upon each other, a floater mounted with ing said dies and adapted to form with said upper die a guide therebetween for a band of sheet material, and means for engaging the upper edge of a band of sheet material within said guide for the same for introduction into the recess between the dies.

9. A die for forming curls comprising a curling die member having a recess therein adapted to receive the metal to be curled and to form a ring of curled metal, said recess having a protuberance therein for forming grooves in the material in the direction of the curl throughout the convolutions of the curled metal.

10. A die for forming curls in sheet metal which comprises a curling die member having a recess therein adapted to receive the metal to curl the same and to form a ring of curled metal, and a steel ball imbedded in the metal of the recess for deforming the metal to be curled throughout the convolutions or the curled metal.

11. A die for forming curls in sheet material which comprises a curling die member having an arcuate recess therein in which the sheet metal is slid for curling and for forming a ring of curled metal, and a plurality of smooth projections extending upwardly from the bottom of the recess for deforming the material to be curled throughout the convolutions of the curled metal.

12. The method of forming a ring-shaped curl from sheet metal which comprises providing means for holding a flat strip of sheet material in the form of a band and forcing the entire material of said band endwise tangentially into a ring-shaped curved cross section mold, closed except for a constricted opening to receive the band, whereby said band of sheet metal will initially follow the curvature of said mold and be curled up by the mold into a unitary com pacted ring of curled metal.

13. The method of forming a closed ring-like structure which comprises forming a pair of strips of sheet material into the form of bands, placing one band within the other on a cylindrical surface with adjacent ends of each band at points remote from each other, and outwardly rolling adjacent cylindrical edges of the bands simultaneously.

14. A machine for forming a ring-shaped curl from sheet material comprising a ring-shaped die having a substantially arcuate recess having a peripheral opening therein of a width equal substantially to the thickness of the material, and means for forcing a ring-shaped sheet of material edgewise completely into the peripheral opening to cause the material to follow the curvature of the recess and form a compact curl.

THEODORE MUNGEN. 

